The coast of Yantai in China has often been ravaged by severe coastal storms together with high elevated water levels, resulting in severe beach erosion and inundation hazards. This study is undertaken to collect essential field data on beach transect profile, beach slope, maximum wave runup level and sediment grain size to assess coastal erosion hazard on Yantai Beach. There are 20 permanent beach transect profiles surveyed every month with RTK-GPS, and three sediment samples were collected from the dune/seawall, beach berm and swash zone. This study has found that the sandy beach backed by the vertical seawall is often flooded at daily high tides, while the beach backed by the sand dune is generally stable. A conceptual model is also applied to estimate shoreline setback distance in n years.
The coast of Yantai is on the north coast of the Shandong Peninsula, the south of the Bohai Sea. Yantai consists of 13 local council areas, of which " councils are on the coast. The topographical breakdown consists of about 50% plain, 40% hilly, 7% mountainous and 3% basin. The urbanized area is about 2,644km2, and its population is 7.0 million in 2016. The total length of the coastline is about 910km, of which the cumulative length of sandy beaches is about 130km. The total number of sandy beaches is 25, of which the longest sandy beach is 17.3km and the shortest one is 260m.
The coast of China is often exposed to tropical cyclones together with storm surges and large storm waves (Sousounis et al, 2008), resulting in great losses of coastal economy and human lives. For example, the 2007 cyclone generated large coastal waves and elevated coastal water levels by 1.5∼2m in Laizhou Bay, 1.1∼1.6m in Longkou, and 1.3m at Yantai Port, resulting in heavy losses of US$120 million coastal economy and 193 human lives (You et al, 2017). The storm-generated high surge levels and large coastal waves are direct causes of coastal erosion (see Fig.1). Most recently, the local government of Yantai has initiated the 5-year coastal plan (2016–2020) to address coastal erosion problems. This five-year coastal plan has been financially supported partially by the national Blue Bay Remediation Action Plan to combat coastal pollution and beach erosion problems in China. The national action plan started in 2010–2014, and will continue for 2016–2020. There are about 66 coastal bays and estuaries selected nationally, and each of the 66 projects is funded for US$90∼150 million. On the coast of Yantai, Zhifu Bay and Laizhou Bay are remediated under the national blue bay action plan.